1. Field of the Invention
This invention relates generally to the mounting, dismounting and balancing of tires on a rim, and, more particularly, to an apparatus and method of balancing, mounting, dismounting and cutting of tires from wheels while the wheels remains attached to a vehicle.
2. Description of Related Art
Applicant""s U.S. Pat. No. 6,247,516, issued on Jun. 19, 2001, and his pending application, Ser. No. 09/895,626, filed Jun. 29, 2001, describe tire changer and mounting apparatus, that also cut tires on a rim. The disclosure of U.S. Pat. No. 6,247,516 (xe2x80x9c""516xe2x80x9d) and pending application Ser. No. 09/895,626 are incorporated herein, in their entireties, by this reference thereto.
The devices and methods in the ""516 patent and in pending application Ser. No. 09/895,626 are drawn to mobile devices that mount or dismount and cut a single tire from or to a wheel while the wheel remains on a vehicle. These devices and methods perform extremely well, and the apparatus and method of the present invention are considered to be patentable extensions thereof.
In particular, the apparatus and method of the present invention are directed to improvements in removing one or more tires at a time from wheels secured to a vehicle and to the accurate balancing of one or more tires mounted on wheels secured on a vehicle.
The present invention also includes improvements in removing tires from wheels secured to a vehicle comprised of modified dowels in which knives for cutting the tires are held. These modified dowels include plastic caps secured to outer ends of the dowels to provide protection when the dowel end contacts a flange of a wheel. The dowels are also capable of being pulled outwardly to extended positions and to self-retract back to normally retracted positions. This movement allows each dowel, when operated correctly, to be pulled outwardly as it comes into contact with the sidewall of a tire which is being turned by a rotating drum. This outward movement helps to bring the dowel into a gentle diametric contact with a rim of a wheel (protected by the plastic cap) where it will be in the best position to work beads of the tire in relation to a flange of the wheel; whether it is breaking the seal of the tires"" bead to the wheel flange, or simply displacing the bead of the tire over the flange of the wheel. By having the dowels xe2x80x9cautomaticallyxe2x80x9d move towards the flange of the rim, a tight fit between the dowel and a wheel flange is accomplished with little effort. This is especially important on the inside wheel flange of a wheel which is often under a vehicle and more difficult to see by an operator, particularly when using a mobile apparatus of the invention.
The ability of the dowels to extend allows one dowel to be pulled outwardly and made to run against one of the wheel flanges while the other remains retracted. With the dowels in this position, the seal of a tires"" bead is more easily broken from the opposite wheel flange. This ability of the dowels to move provides the mobile apparatus with increased stability, in particular, during a small percentage of the time when the seal between the tires"" bead and the wheel flange is tough to break. In a mobile apparatus it is possible that the apparatus (because of its weight) might slide under the tire and wheel when a nonretracting dowel is operated in a manner to try and break the seal of a tires"" bead to a wheel. By allowing the dowels to move, and placing an opposite dowel against the flange of the wheel, the apparatus will be prevented from slipping under the tire as it tries to break a difficult tire bead""s seal. The plastic caps protect the wheel during this operation.
Additionally, it is well known to attempt to balance a tire while it remains on a vehicle or wheel. Traditionally, a vehicles"" engine is used to drive the axle of a vehicle, or a xe2x80x9cspinnerxe2x80x9d (an independent machine capable of spinning the vehicles"" tire and wheel) is connected to a non-drive train axle and used to rotate the tire and wheel to a sufficient speed in order to electronically sense, or xe2x80x9cpickup,xe2x80x9d any vibration created by any imbalance in the tire wheel as they are spinning on the vehicle. The known electronic sensing device used to xe2x80x9cpickupxe2x80x9d such vibration is attached to a portion of the under side of the car that supports the tire and wheel assembly. The laws of gravity dictate that the point of imbalance of a tire and wheel is located along the circumference of the tire where the greatest degree of vibration is generated. This occurs when the heavy side of the circumference has rotationally descended to its lowest point and begun to move rotationally upward. In order to balance a tire in this manner, there are two pieces of information needed: 1. the amount of weight needed to offset the heavy side of the circumference of the tire, and 2. at what point along the circumference this offsetting weight should be placed. Calculations are performed to determine the amount of weight associated with any given amount of vibration detected through the electronic sensing device mentioned above. In order to mark the location along the circumference of the tire for the needed counterweight, a strobe light is used and aimed at the tire and wheel assembly by an operator. When the heavy portion of the circumference reaches the bottom of its arc (hereafter referred to as six o""clock for simplicity) the strobe light flashes on the tire. The desired position for placement of a weight on the tire and wheel is then marked by an operator using chalk, tape, or the like. The operator then places the amount of weight determined by the sensing device at the six o""clock position marked by the operator using the strobe light to bring the tire and wheel into balance.
This method of balance has both good and bad attributes: one good attribute is that it rotates and senses the imbalance of all moving parts (tire, wheel, rotor, drum, axle, wheel cover and wheel lug nuts, as well as the connection of the wheel to the axlexe2x80x94which can be non-concentric). This is more than an off-the-car balancer or balancing machine is capable of accomplishing. A bad attribute to this method of balancing is that it is only capable of detecting imbalance in one vertical plane.
However, the most common form of balancing a tire and wheel is what is referred to as xe2x80x9coff-the-carxe2x80x9d balancing. A balancing machine, called a balancer, typically made up of a spindle and hub is used. A tire and wheel assembly is first removed from a vehicle and quickly mounted on this machine. The spindle of the balancer is connected to a motor that is capable of spinning the tire and wheel assembly. The spindle is also connected to sensitive electronic motion devices that can electronically xe2x80x9cpickupxe2x80x9d the imbalance of the tire and wheel assembly when it is spinning. Because the tire and wheel assembly is affixed to the spindle, and, therefore, the electronic sensing devices, the balancing machine will be able to tell the operator where and how much counterweight to place along the circumference of the tire by electronically informing the operator where the six o""clock position is in relation to the tires"" imbalance. Furthermore, by initially programming the balancer with information about the wheel and tire (width, offset, diameter) the balancing machine can make more detailed calculations and split the required weights between two planes (inner and outer rim flanges) and take into account horizontal as well as vertical imbalance. These calculations are standard mathematical equations and are feasible and applicable to the process of balancing a tire and wheel using an xe2x80x9coff-the-carxe2x80x9d balancer, since the tire and wheel assembly is connected to a rotating spindle that is itself connected to the sensing devices to provide the necessary information.
The method of balancing a tire and wheel with the described xe2x80x9coff-the-carxe2x80x9d balancer allows for more information and control of that information than the xe2x80x9con-the-carxe2x80x9d balancing technique because the sensing devices are connected to the revolving tire and wheel by way of the spindle. The obvious disadvantage is that the xe2x80x9coff-the-carxe2x80x9d balancer only balances the tire and wheel assembly. The present invention overcomes the known problems with balancing machines and methods, and combines the best features of these known machines and methods for balancing tires in a unique and novel manner.
There still exists a need in the art for an apparatus and method that more efficiently allows tires to be dismounted from or mounted to wheels without taking the wheels off the vehicle. And, there also exists a need in the art for an apparatus and method that easily balances tires on wheels, held on a vehicle.
Accordingly, it is a general object of the present invention to provide an improved tire balancing and changing apparatus. It is a particular object of the present invention to provide an improved tire balancing and changing apparatus and an improved method for using the same. It is another particular object of the present invention to provide an improved tire balancing and changing apparatus that more easily allows the changing of a plurality of tires from wheels while the wheels are still attached to a vehicle. It is a further particular object of the present invention to provide an improved tire balancing and changing apparatus and method that includes a plurality of drums for spinning the tires and wheels of a vehicle, while the wheels are still attached to the vehicle. It is yet a still further particular object of the present invention to provide an improved tire balancing and changing apparatus and method of use that allows match mounting of tires to wheels on a vehicle. It is a still further particular object of the present invention to provide a tire balancing and changing apparatus secured in a bay within a building, or the like. And, it is yet another particular object of the present invention to provide an improved balancing and changing apparatus having rotatable drums and means for extending dowels for more easily removing tires from wheels mounted on a vehicle.
These and other objects of the present invention are achieved by providing a tire balancing and changing device having a plurality of drums for movement into contact with a vehicle""s tire and wheel assemblies to enable the tires of the vehicle to be balanced and/or changed while the wheels remain on the vehicle. The tire balancing and changing device of the present invention includes a plurality of pairs of dowels to mount and dismount tires, driving means to operate the dowels and to rotate tire and wheel assemblies, and sensing means to enable the tires to be balanced on the wheels on the vehicle.
The novel method of the present invention includes the steps of positioning a vehicle on a body in the device; taking the weight of the vehicle off the tires and wheels; removing and replacing at least some of the tires on the vehicle as required; and moving drums into contact with properly inflated tires on wheel assemblies and rotating the drums to rotate the tire and wheel assemblies to balance the tires and wheels on the vehicle.